Integrated flexibility characterization and measurement of distributed multi-energy systems considering temporal coupling constraints

The integrated flexibility of distributed multi-energy systems (DMES) has been recognized as a valuable balancing resource to the centralized energy system, which can be characterized by an integrated flexible region (IFR) of multiple energy inputs. Notably, the IFR is only captured for one single period in previous studies, whereas the time coupling in consecutive periods has a significant impact on the integrated flexibility. This paper proposes a modified IFR-based approach to characterize and measure the integrated flexibility of DMES considering the temporal coupling constraints. First, operation constraints of the DMES are formulated, followed by a vertex search method to obtain the IFR, i. e, a polytope that visualizes those operation constraints. Then, an approximation approach is proposed to decompose the original IFR into a series of lower-dimension IFRs, each of which corresponds to a specific period. The influence of states of adjacent periods is directly reflected by the position change of the vertices. The decoupled IFRs can be incorporated conveniently into the multi-period economic dispatch of the centralized energy system. Moreover, the Volume of the IFRs (VFR) is introduced as an index to quantify the flexibility of the DMES. The performance of the proposed methods is verified by the case studies.